1. Field of the Invention
The present invention generally relates to an apparatus for measuring the locking force or the tightening torque, in particular to an apparatus capable of controlling, tracking and measuring the tightening torque and the locking force, and a method for controlling, tracking, measuring and calibrating thereof.
2. Description of the Related Art
Fastener is used widely in miscellaneous products. The bigger the product size is, the greater the locking force for fastener it needs. However, when fasteners are utilized to tighten components, how to determine whether or not the locking force or the tightening torque applied to the fasteners has reached the desired standard? Generally speaking, conventional method usually utilizes a tightening tool and ultrasonic device to measure the locking force or the tightening torque. However, tightening tool can just measure the magnitude of the tightening torque of the fastener and the user thereof tends to excessively exert force on the fastener, so that the fastener is inclined to be damaged or broken. For example, when a fastener is utilized to tighten up a wheel rim of a car, excessive force exerted to the fastener will make the locking force applied to the fastener exceed the tolerable maximum locking force thereof, which would result in damages to the fastener or even the wheel rim. Accordingly, when a car moves at high speed or suffers great impact force, the damaged fastener tends to be fractured and thereby causes the wheel rim to drop from the car, which would bring about a major car accident. Besides, as being of high cost and inconvenient to use, the ultrasonic detector fails to be universalized.
On the other hand, in order to obtain a precise measurement result, the fastener with built-in computing devices, such as built-in sensor, data transmitter and microprocessor, is utilized in some available torque measurement devices, which significantly increases the manufacturing cost of the fastener. Furthermore, another way to increase the precision of the measurement result is to connect the load cell with the measurement device electrically by wire and then place the fastener on the load cell to perform tightening operation, such that the measurement device can display the locking force through the load cell. However, the load cell electrically connected to the measurement device by wire will retard the measurement operation.
Accordingly, conventional methods for measuring the tightening torque and the locking force have problems that the measurement result is not accurate enough. The measurement is of high cost and not convenient to users.